1. FIELD Field of the Invention
This invention relates to a new and useful porous, pressure sensitive adhesive tape, and more particularly to a surgical tape comprising a highly porous plastic film backing material coated on one side with a pressure sensitive adhesive.
2. DESCRIPTION Description of Prior Art
It has long been known that surgical adhesive tape should be permeable to water vapor in order to prevent maceration of the wound site due to occlusion of water arising from transepidermal discharge of moisture from the body. A substantially non-porous tape which interferes with this essential body function may result in severe skin irritation.
In addition to being porous or breathable, surgical tapes are also desirably finger tearable so that strips of tape may be torn rather than cut to a size suitable for the particular wound. The tape must have sufficient tensile strength however, to restrain the wound in an immobile position for healing, and sufficiently flexible to conform to the surface of the skin and to move with movement of the skin.
Surgical tapes of the prior art have been constructed of a variety of backing materials and adhesives. Porous backing materials of woven or non-woven fabrics and perforated plastic films have been suggested in U.S. Pat. Nos. 3,039,893 and 3,523,846. Another porous backing formed of non-woven rayon textile fiber is described in U.S. Pat. No. 3,121,021. Microporous films of plasticized polyvinyl chloride and woven, non-woven, and knitted fabrics are described in U.S. Pat. No. 3,645,835.
Plastic films are desirable as backing materials because they are light, flexible, thin, transparent and easily cleanable. Except for certain limited microporous plastic compositions, porosity of plastic films has typically been obtained mechanically by punching holes in the film. Such perforated films of the prior art have generally lacked the combination of high porosity, dimensional stability, tensile strength, and tearability required of a surgical tape.
It is accordingly an object of the present invention to provide an improved surgical tape having a porous plastic backing material. It is a further object of this invention to provide a porous surgical tape which is substantially unaffected by moisture or body fluids and has good dimensional stability, flexibility, and tensile strength. It is also an object of this invention to provide a plastic surgical tape which is biaxially oriented and readily tearable in two directions. Yet other objects of this invention will be apparent from the ensuing description and claims.